Industrial processes are known, which transfer envelopes from a feeding line, e.g. conveying means, to corresponding receiving magazines, the so-called “stackers”, where the envelopes are piled up in metallic baskets, whose dimensions are adapted to the dimensions of envelopes.
The latter, housed in the baskets, are then picked up by mechanical arms, which place them inside box-like containers, disposed side by side and vertically.
However, these processes must be interrupted when the envelope size is changed: in fact, in these cases, an operator must intervene manually to adapt the dimensions of the baskets to the new dimensions of the envelopes, which are to be housed there, which results in a waste of time.